In an experiment that seems to come out of science fiction, American neuroscientists connected with cables the brains of two rats, allowing them to perceive and accept the stimuli of each other, even at a distance of thousands of kilometers.
Tricking the brain
“Can we trick the brain? Can it process signals from another body?” That was the question Miguel Nicolelis of Duke University in North Carolina tried to answer. And according to a study published in the journal «Scientific Reports», the answer is yes.
This unusual experiment is the first of its kind, claims Nicolelis, known from earlier work on connections between the brain and computers. In 2000 Nicolelis had presented a system that allowed a monkey to use a robotic arm via mental commands, and recently tested a brain implant that allowed mice to perceive light with the sense of touch.
A future for paralyzed patients
The ultimate goal of the researcher is to create a robotic exoskeleton that could be used by paralyzed patients with the help of mental commands. The latest study is not directly related to this goal, but it could help in efforts to capture and interpret brain signals.
The experiment was performed with two rats, one of which was in North Carolina and the other in Brazil. Both animals were trained to press a particular lever when a certain light bulb switched on in order to be rewarded with a sip of water.
Electrodes implanted in the motor cortex
Both animals were implanted with electrode arrays in the primary motor cortex of the brain, which controls and coordinates the movements.
One of the two rats played the role of the transmitter, or “encoder”. When it pressed the lever, the signals from the motor cortex of its brain were transmitted to the second rat through an Internet connection.
The second rat, or “decoder” saw the lights switched on, without knowing which was the right one. In order to manage to drink water, it had to rely on the signals received from its remote “partner”.
Proper interpretation in 70% of cases
Indeed, the second rat pressed the correct lever in 70% of cases, which means that its brain had learned to accept and interpret brain signals of the other rat.
The research team claims to have reached similar encouraging results in experiments with sensory stimuli. For example, the decoder rat could understand if the encoder rat touched with its whiskers the entrance of a narrow or a spacious corridor.
However, the study was greeted with mixed reactions. “I believe that is a fascinating publication,” said Ron Frosting, a neuroscientist at the University of California at Davis, to the New York Times. He characterized the study as a “proof in principle” for direct communication between minds.
At the same time, another expert, Andrew Stewart of the University of Pittsburgh believes that the study is “simplistic”. Dr. Stewart questioned the reliability of the results, saying that the rat decoder pressed the right lever only in seven out of ten cases, while even if it pressed levers by chance it would succeed in half of cases.